Uptime Kuma can be used to monitor uptime SLOs and provide alerts for downtime. This can be installed with the Docker Compose file found here.

Email Notifications

Email notifications can be setup by navigating to Settings > Notifications > Setup Notification. Select Email (SMTP) as the notification type and fill in the rest of the fields based on the guide for setting up email notifications in Proxmox as the settings are the same. Do note, however, that the From Email field can be setup to show a specific sender (useful for identifying alerts, filtering rules, etc.). This is in the format "Sender Display Name" <[email protected]>.